This invention relates to a data processing apparatus and, more particularly, to a data processing apparatus having an enlargement/reduction functions capable of setting different magnifications in different directions.
In a conventional data processing apparatus, data, e.g., image data of a large amount of documents are optically read by a two-dimensional scanning device. The data read by the two-dimensional scanning device are displayed on a display device such as a CRT (cathode-ray tube) display. The image data displayed on the CRT display are subjected to rotation, enlargement, reduction, movement, extraction, or synthesis with other documents to be edited to obtain an objective document. The edited document is sequentially stored on a storage medium such as an optical disk, or is output in a visible state for an operator using an output apparatus such as a CRT display or a printer.
When a character or an image displayed on the CRT display is to be enlarged or reduced, the enlargement or reduction magnifications in the horizontal and vertical directions of the character or image are equal to each other. More specifically, an original character or image is equally enlarged or reduced to obtain a resultant character or image, and the shapes of the characters or images before and after the enlargement/reduction are similar to each other. For this reason, when an operator performs an edit operation of characters or images using the apparatus, the image cannot be displayed in an arbitrary area on the CRT display. This is because an image to be displayed on the CRT display can only be enlarged or reduced at equal horizontal and vertical magnifications.